Connector

ABSTRACT

A connector comprising a body ( 1 ) having a throughway ( 5 ) which is open at one end ( 4 ). A shoulder ( 8 ) in the throughway faces the open end and supports an O-ring ( 9 ). A collet ( 3 ) in the open end of the throughway has a plurality of legs ( 18 ) extending away from the open end, each engaging with the body and having an inwardly facing tooth to grip, in use, a tube in the throughway. The body has a plurality of fingers ( 11 ) extending to the open end. The connector further comprises a cap ( 2 ) fitting over the open end of the body and extending from the open end towards the opposite end. The cap has a plurality of recesses ( 23 ) in a wall at the open end into each of which a finger is retained by a snap fit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/512,822, filed Oct. 13, 2014, U.S. Pat. No. 9,322,499, which claimspriority to United Kingdom Application No. 1317990.8, filed Oct. 11,2013, the contents of which are incorporated herein by specificreference.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates to a connector for joining plastic tubes.

2. The Relevant Technology

In particular, the present invention relates to a connector comprising abody having a throughway which is open at one end, a shoulder in thethroughway which faces the open end and supports an O-ring; a collet inthe open end of the throughway and having a plurality of legs extendingaway from the open end, each engaging with the body and having aninwardly facing tooth to grip, in use, a tube in the throughway. Such aconnector will subsequently be described as “of the kind described”.

Connectors of the kind described have found widespread use inapplications for connecting plastic tubes and the like, for example, inplumbing, electrical cables and fibre optic applications. They provide aquick and reliable method of joining two cables together or connecting acable to another component.

A conventional connector of the kind described has a two-part bodyassembly. This consists of a body which is provided with the internalfeatures such as the shoulder described above and a cap which is fittedover the body and is ultrasonically welded in place. This is necessaryas the profile of the body cannot readily be moulded in a single piece.

While the ultrasonically welded cap has a number of advantages and hasproved commercially successful, it does have a number of drawbacks. Thewelding process requires complex equipment. The materials of the cap andbody must be compatible with one another and suitable for ultrasonicwelding, and the cap and the body must be sufficiently thick and robustto allow the welding.

In an attempt to address these problems, it has been proposed (forexample in the John Guest 3 mm Miniature Straight Connector, Product#DS-NC2129) that the end of the cap opposite to the open end is providedwith an inwardly facing annular shoulder which is snap fitted over acomplimentary outwardly facing annular shoulder on the body.

This overcomes the above problems with ultrasonic welding. However, itintroduces problems of its own. The snap ring on the cap has to expandradially outwardly as it is pushed into the body. This puts considerablestrain on the cap which can lead to cracking. Also, as the annular snapring snaps into place behind the shoulder on the body, this snappinginto place can actually cause impact cracking.

Further, when in situ if a bending load is applied to the connector, thebending force is such that it tends to pull the snap ring away from theshoulder on one side, while on the opposite side, the snap ring can beforced towards the shoulder, these stresses can cause the cap to crackor become dislodged from the body.

SUMMARY OF THE INVENTION

According to the present invention, a connector of the kind described ischaracterised in that the body has a plurality of fingers extending tothe open end; the connector further comprising a cap fitting over theopen end of the body and extending from the open end towards theopposite end, the cap having a plurality of recesses in a wall at theopen end into each of which a finger is retained by a snap fit.

The present invention has two features which improve upon the abovementioned prior art. Firstly, it has a plurality of fingers to providethe snap fit, and secondly the snap fit is now in the end of the capadjacent to the open end, rather than being at the opposite end as withthe prior art. Thus, when the cap is put in place, it is individualfingers of the body which flex inwardly. These are therefore subjectedto far less stress than an annular ring which is deflected outwardly.

Further, as the snap fit engagement is now at the open end of theconnector, the forces experienced at this point when the connector issubjected to a bending load are significantly less than those which areexperienced at the opposite end of the cap in the prior art. Also, asthe snap fit engagement is between a plurality of discrete fingers,rather than an annular ring, it is far more difficult to dislodge thecap as there is no tendency for the fingers to be “peeled” off therecesses with which they engage.

It is possible that each recess in the wall does not extend all the waythrough the wall. However, preferably, each recess extends fully throughthe wall. This means that each finger is visible at the end wallallowing visual confirmation that the cap and body have correctlyengaged.

The inner wall of the end cap may be featureless such that, uponassembly, the cap and body are visually aligned by the person doing theassembling. Alternatively, the inner wall of the cap may be providedwith parallel guideways to guide each finger into the recess. However,preferably, an inwardly facing surface of the cap is provided with aguideway associated with each recess, the guideway having a wide mouthat the end opposite the wall and tapering towards the recess.Preferably, each mouth subtends an angle of at least 50°. Thisfacilitates the assembly process as the assembler does not need toprecisely align the cap and the body. Instead, the body can be insertedinto the cap out of alignment and the guideways will guide the fingersto the correct position at the end of the cap.

BRIEF DESCRIPTION OF THE DRAWINGS

An example of a connector in accordance with the present invention willnow be described with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of the cap and body prior to assembly;

FIG. 2 is a view similar to FIG. 1, but with the front part of the capand a part of the body cut away;

FIG. 3 is a view similar to FIG. 2 with the cap and body assembled; and

FIG. 4 is a perspective view showing the cap and body assembled prior toinsertion of the collet ring.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The connector broadly consists of three main components, namely the body1, cap 2 and collet ring 3. As shown in the drawings, the connector is adouble-ended connector having a cap 2 at each end. The connector issuitable for connecting two tubes together. However, the invention couldequally apply to a single-ended connector to connect the tube to anunderlying structure. Alternatively, the double-ended connector could beprovided with a connector according to the present invention at one endand a different type of connector at the opposite end.

The body 1 is open at one end 4 and has an axial throughway 5 extendingthrough the connector. The throughway 5 is a stepped bore having anarrow diameter portion 6 with a diameter which correspondsapproximately with the inner diameter of the tube. This portion 6terminates at a first shoulder 7 facing the open end 4 against which thetube abuts, in use. A second shoulder 8 provides a further outward stepfor the bore and is arranged to receive an O-ring 9 which seals, in use,against the tube. Also in the vicinity of this region is an outwardlyextending annular flange 10 which provides an end stop for the cap 2 asbest shown in FIG. 4. It is noted that flange 10 is the maximum outerdiameter of body 1 and, as depicted in FIG. 4, is equal to the maximumouter diameter of cap 2.

Extending towards the open end 4 of the body are four fingers 11 whichare evenly spaced about the axis. Although four are illustrated, theremay be more or less than this in practice and they do not necessarilyneed to be evenly spaced. Each finger is provided at the open end 4 witha radially outwardly projecting barb 12. Each barb 12 is tapered and hasan inside shoulder 30 and an outside face 32 that intersect at anoutside corner 34. Each finger extends to a ring 13 as best shown inFIG. 1. Each of the fingers 11 is flared away from the open end and thisflared portion has a greater thickness than the thickness of the ring 13to provide a tapering profile for the purpose set out below.

The end cap 2 has a generally annular shape that extends between a firstend 33 and an opposing second end 35. It has an outer wall 14 extendingalong its full length and terminating at an end wall 15 which is at theopen end 4 once the cap is fitted in place. Outer wall 14 has aninwardly facing inside face 20 and an opposing outwardly facing outsideface 38 that both extend to end wall 15. The end wall 15 extendsradially inwardly to an inner wall 16 which extends away from an openend 4 for a short distance.

This inner wall 16 provides a shoulder for engagement with the colletring 3 as is known in the art. The collet ring 3 has an end ring 17 fromwhich a plurality of resilient legs 18 extend away from the open end 4.The ends of the legs extend radially outwardly to define a shoulder 19.The collet ring 3 is inserted into the collet such that the legs 18deflect radially inwardly until the shoulder 19 passes the inner wall16. In use, when a tube inserted into the connector is pulled in adirection which would tend to pull it out of the connector, there areteeth (not shown) on the inner surface of the collet legs which grip theouter surface of the tube. This pulling force causes the shoulder 19 toengage with the inner wall 16 causing inward deflection of the legsincreasing the gripping force on the tube. This operation of the colletis entirely conventional and is well understood in the art.

The inside face 20 of the outer wall 14 is provided with a profiledsurface which matches the profile of the ring 13 described below. Thisprofile features four guideways 21, one for each finger 11 which have awide mouth 22 at the end opposite to the end wall 15, which then taperstowards a window/recess 23 in the end wall 15. Each window/recess 23passes from inside face 20 to outside face 38 so as to pass throughouter wall 14. Each window/recess 23 also passes through end wall 15.Outer wall 14 of cap 2 includes an annular tapered section 40 thatencircles throughway 5 of body 1. Annular tapered section 40 extends toend wall 15 with each window/recess 23 intersecting therewith. Annulartapered section 40 includes a plurality of tapered portions 42 that aredisposed directly adjacent to each window/recess 23 on the side towardfirst end 33 of cap 2.

When the cap is placed on the body, any misalignment between the fingers11 and the windows/recesses 23 can be accommodated by the wide mouth 22which will alter the radial alignment between the body 1 and the cap 2as the cap is pushed into the body until the fingers 11 line up with thewindows/recesses 23.

As the cap 2 is pushed into place, the fingers 11 will deflect inwardly.As they are thin components (compared to an annular shoulder), they canreadily accommodate this small amount of inward deflection withoutcausing undue stress on the material. As the cap 2 reaches the positionin which it is fully engaged with the body 1, the barbs 12 on the end ofthe fingers 11 snap into the windows/recesses 23 to retain the cap 2 inplace. The impact force of a relatively narrow finger 11 snapping intoplace is a fraction of the force of the annular shoulder of the priorart snapping into place. The barbs 12 are visible at thewindows/recesses 23 allowing an assembler to confirm that the cap 2 isin the correct position in the body 1. The assembly process is thereforeone which is very easy and reliable and does not place undue stress onthe body 1 or the cap 2.

As depicted in FIGS. 3 and 4, it is noted that when barbs 12 arereceived within windows/recesses 23, outside face 32 of each barb 12 isflush with outside face 38 of tapered section 40 and tapered portions42. Furthermore, outside face 32 and outside corner 34 of each barb 12is openly exposed through outside face 38 of cap 2 as a result ofwindows/recesses 23. In addition, outside face 38 of each taperedportion 42 of cap 2 is aligned with outside face 32 of the adjacent barb12 and is disposed at substantially the same angle as the outside face32 of the adjacent barb 12 so that outside face 32 of barb 12 is acontinuation of outside face 38 of each tapered portion 42 of cap 2.

If a bending force is applied to the tube inserted in a connector, thebending force is effectively centred around the open end 4 and willtherefore be lower at this point than it is at a position further fromthe open end. Thus, although the bending load may have some tendency tocause the end of the cap opposite to the open end to be separated fromthe body, this can be tolerated as no part of the fixing is done at thisend. The fixing at the open end remains largely unaffected by such aforce.

What is claimed is:
 1. A connector comprising: a body having athroughway which is open at one end, a shoulder in the throughway facesthe open end and supports an O-ring, the body having a plurality offingers extending to the open end with a barb projecting from eachfinger, each barb having an outside face; a collet having a plurality oflegs that are at received within the open end of the body, each of theplurality of legs having an inwardly facing tooth; and a cap fittingover the plurality of fingers of the body, the cap having an encirclingouter wall with an inwardly facing inside face and an outwardly facingoutside face, the outside face being spaced radially outward from theinside face, a plurality of spaced apart windows extend laterallythrough the outer wall so as to extend through the inside face andthrough the outside face, each barb being received within acorresponding window.
 2. The connector according to claim 1, wherein theoutside face of each barb is openly exposed through the outside face ofthe cap.
 3. The connector according to claim 1, wherein at least aportion of the outside face of each barb is flush with the outside faceof the cap.
 4. The connector according to claim 1, further comprising:the barb of each finger being tapered; and a portion of the outside faceof the outer wall of the cap adjacent to each barb being tapered.
 5. Theconnector according to claim 4, wherein the tapered portion of the capadjacent to each barb has an outside face, the outside face of eachtapered portion of the cap being aligned with the outside face of theadjacent barb and being disposed at substantially the same angle as theoutside face of the adjacent barb.
 6. The connector according to claim4, wherein the outside face of the outer wall of the cap comprises anannular tapered section that encircles the throughway of the body and isdisposed adjacent to the barbs of the fingers, the annular taperedsection comprising each of the tapered portions.
 7. The connectoraccording to claim 6, wherein the plurality of windows extend throughthe annular tapered portion.
 8. The connector according to claim 1,wherein each barb has an inside shoulder, the inside shoulder of eachbarb intersecting with the outside face of the corresponding barb at anoutside corner, the outside corner being openly exposed.
 9. Theconnector according to claim 1, further comprising a plurality ofelongated guideways recessed on the inside face of the cap, each fingerbeing received within a guideway.
 10. The connector according to claim9, wherein each of the guideways is tapered.
 11. The connector accordingto claim 1, wherein each barb is snap fit within a corresponding window.12. The connector according to claim 1, wherein the cap furthercomprises: an annular inner wall disposed radially inward from the outerwall, the inner wall at least partially encircling an opening in whichthe collet is received; and an end wall extending between the inner walland the outer wall.
 13. A connector comprising: an annular bodyencircling a throughway which is open at one end of the body, the bodyhaving a shoulder in the throughway which faces the open end and havinga plurality of fingers that extend to the open end with a barbprojecting from each finger, a central longitudinal axis extends throughthe throughway along a length of the body, each barb having an outsideface that inwardly slopes relative to the central longitudinal axis; anO-ring disposed within the throughway and supported on the shoulder ofthe body; a collet having a plurality of legs that are at receivedwithin the open end of the body, each of the plurality of legs having aninwardly facing tooth; and a cap fitted over the plurality of fingers ofthe body, the cap having an inside face and an opposing outside face, aplurality of spaced apart recesses being formed on the cap into each ofwhich the barb of one of the fingers is received, wherein a portion ofthe outside face of the cap towards the open end of the body inwardlyslopes relative to the central longitudinal axis.
 14. The connectoraccording to claim 13, wherein the portion of the outside face of thecap that inwardly slopes is flush with outside face of at least one ofthe barbs.
 15. The connector according to claim 13, wherein the portionof the outside face of the cap that inwardly slopes is directly adjacentto at least one of the plurality of recesses.
 16. The connectoraccording to claim 15, wherein the outside face of at least one of thebarb is sloped so as to be a continuation of the sloped portion of theoutside face of the cap.
 17. The connector according to claim 13,wherein the body has a maximum outer diameter and the cap has a maximumouter diameter, the maximum outer diameter of the body and the cap beingthe same.
 18. The connector according to claim 13, wherein the recessescomprise windows that extend laterally through the cap between theinside face and the outside face.
 19. The connector according to claim13, wherein the cap further comprises: an annular outer wall having theinside face and the outside face; an annular inner wall disposedradially inward from the outer wall, the inner wall at least partiallyencircling an opening in which the collet is received; and an end wallextending between the inner wall and the outer wall.
 20. A connectorcomprising: a body having a throughway which is open at one end, ashoulder in the throughway faces the open end and supports an O-ring,the body having a plurality of fingers extending to the open end with abarb projecting from each finger, each barb having an outside face; acollet having a plurality of legs that are at received within the openend of the body, each of the plurality of legs having an inwardly facingtooth; and a cap fitting over the plurality of fingers of the body, thecap having an inwardly facing inside face and an outwardly facingoutside face, a plurality of spaced apart windows extend through the capbetween the inside face and the outside face, each barb being receivedwithin a corresponding window, a plurality of elongated guidewaysrecessed on the inside face of the cap with each of the guideways beingtapered, each finger being received within a guideway.
 21. The connectoraccording to claim 20, wherein the cap further comprises: an annularouter wall having the inside face and the outside face; an annular innerwall disposed radially inward from the outer wall, the inner wall atleast partially encircling an opening in which the collet is received;and an end wall extending between the inner wall and the outer wall.